diff --git a/arduino-ide-extension/src/electron-main/arduino-electron-main-module.ts b/arduino-ide-extension/src/electron-main/arduino-electron-main-module.ts
index 5f4a43e0..f1b0f639 100644
--- a/arduino-ide-extension/src/electron-main/arduino-electron-main-module.ts
+++ b/arduino-ide-extension/src/electron-main/arduino-electron-main-module.ts
@@ -1,15 +1,20 @@
 import { ContainerModule } from 'inversify';
 import { JsonRpcConnectionHandler } from '@theia/core/lib/common/messaging/proxy-factory';
 import { ElectronConnectionHandler } from '@theia/core/lib/electron-common/messaging/electron-connection-handler';
+import { ElectronMainWindowService } from '@theia/core/lib/electron-common/electron-main-window-service';
 import { ElectronMainApplication as TheiaElectronMainApplication } from '@theia/core/lib/electron-main/electron-main-application';
 import { SplashService, splashServicePath } from '../electron-common/splash-service';
 import { SplashServiceImpl } from './splash/splash-service-impl';
 import { ElectronMainApplication } from './theia/electron-main-application';
+import { ElectronMainWindowServiceImpl } from './theia/electron-main-window-service';
 
 export default new ContainerModule((bind, unbind, isBound, rebind) => {
     bind(ElectronMainApplication).toSelf().inSingletonScope();
     rebind(TheiaElectronMainApplication).toService(ElectronMainApplication);
 
+    bind(ElectronMainWindowServiceImpl).toSelf().inSingletonScope();
+    rebind(ElectronMainWindowService).toService(ElectronMainWindowServiceImpl);
+
     bind(SplashServiceImpl).toSelf().inSingletonScope();
     bind(SplashService).toService(SplashServiceImpl);
     bind(ElectronConnectionHandler).toDynamicValue(context =>
diff --git a/arduino-ide-extension/src/electron-main/theia/electron-main-application.ts b/arduino-ide-extension/src/electron-main/theia/electron-main-application.ts
index c096daf6..f3727aa7 100644
--- a/arduino-ide-extension/src/electron-main/theia/electron-main-application.ts
+++ b/arduino-ide-extension/src/electron-main/theia/electron-main-application.ts
@@ -13,7 +13,7 @@ import { SplashServiceImpl } from '../splash/splash-service-impl';
 @injectable()
 export class ElectronMainApplication extends TheiaElectronMainApplication {
 
-    protected windows: BrowserWindow[] = [];
+    protected _windows: BrowserWindow[] = [];
 
     @inject(SplashServiceImpl)
     protected readonly splashService: SplashServiceImpl;
@@ -34,7 +34,7 @@ export class ElectronMainApplication extends TheiaElectronMainApplication {
     async createWindow(asyncOptions: MaybePromise<TheiaBrowserWindowOptions> = this.getDefaultBrowserWindowOptions()): Promise<BrowserWindow> {
         const options = await asyncOptions;
         let electronWindow: BrowserWindow | undefined;
-        if (this.windows.length) {
+        if (this._windows.length) {
             electronWindow = new BrowserWindow(options);
         } else {
             const { bounds } = screen.getDisplayNearestPoint(screen.getCursorScreenPoint());
@@ -63,14 +63,14 @@ export class ElectronMainApplication extends TheiaElectronMainApplication {
                 splashScreenOpts
             }, this.splashService.onCloseRequested);
         }
-        this.windows.push(electronWindow);
+        this._windows.push(electronWindow);
         electronWindow.on('closed', () => {
             if (electronWindow) {
-                const index = this.windows.indexOf(electronWindow);
+                const index = this._windows.indexOf(electronWindow);
                 if (index === -1) {
                     console.warn(`Could not dispose browser window: '${electronWindow.title}'.`);
                 } else {
-                    this.windows.splice(index, 1);
+                    this._windows.splice(index, 1);
                     electronWindow = undefined;
                 }
             }
@@ -148,4 +148,8 @@ export class ElectronMainApplication extends TheiaElectronMainApplication {
         }
     }
 
+    get windows(): BrowserWindow[] {
+        return this._windows.slice();
+    }
+
 }
diff --git a/arduino-ide-extension/src/electron-main/theia/electron-main-window-service.ts b/arduino-ide-extension/src/electron-main/theia/electron-main-window-service.ts
new file mode 100644
index 00000000..7a1428ab
--- /dev/null
+++ b/arduino-ide-extension/src/electron-main/theia/electron-main-window-service.ts
@@ -0,0 +1,24 @@
+import { inject, injectable } from 'inversify';
+import { NewWindowOptions } from '@theia/core/lib/browser/window/window-service';
+import { ElectronMainWindowServiceImpl as TheiaElectronMainWindowService } from '@theia/core/lib/electron-main/electron-main-window-service-impl';
+import { ElectronMainApplication } from './electron-main-application';
+
+@injectable()
+export class ElectronMainWindowServiceImpl extends TheiaElectronMainWindowService {
+
+    @inject(ElectronMainApplication)
+    protected readonly app: ElectronMainApplication;
+
+    openNewWindow(url: string, { external }: NewWindowOptions): undefined {
+        if (!external) {
+            const existing = this.app.windows.find(window => window.webContents.getURL() === url);
+            if (existing) {
+                existing.focus();
+                return;
+            }
+        }
+        return super.openNewWindow(url, { external });
+    }
+
+
+}